Added python solutions and corrected 128 to medium (#263)

Author: jordankirkland

Diff for: README.md

@@ -425,7 +425,7 @@ LeetCode
 |140|[Word Break II](https://leetcode.com/problems/word-break-ii/)| [C++](./algorithms/cpp/wordBreak/wordBreak.II.cpp)|Hard|
 |139|[Word Break](https://leetcode.com/problems/word-break/)| [C++](./algorithms/cpp/wordBreak/wordBreak.cpp)|Medium|
 |138|[Copy List with Random Pointer](https://leetcode.com/problems/copy-list-with-random-pointer/)| [C++](./algorithms/cpp/copyListWithRandomPointer/copyListWithRandomPointer.cpp), [Python](./algorithms/python/CopyListWithRandomPointer/copyRandomList.py)|Hard|
-|137|[Single Number II](https://leetcode.com/problems/single-number-ii/)| [C++](./algorithms/cpp/singleNumber/singleNumber.II.cpp)|Medium|
+|137|[Single Number II](https://leetcode.com/problems/single-number-ii/)| [C++](./algorithms/cpp/singleNumber/singleNumber.II.cpp), [Python](./algorithms/python/SingleNumberII/SingleNumberII.py)|Medium|
 |136|[Single Number](https://leetcode.com/problems/single-number/)| [C++](./algorithms/cpp/singleNumber/singleNumber.cpp)|Medium|
 |135|[Candy](https://leetcode.com/problems/candy/)| [C++](./algorithms/cpp/candy/candy.cpp)|Hard|
 |134|[Gas Station](https://leetcode.com/problems/gas-station/)| [C++](./algorithms/cpp/gasStation/gasStation.cpp)|Medium|
@@ -434,7 +434,7 @@ LeetCode
 |131|[Palindrome Partitioning](https://leetcode.com/problems/palindrome-partitioning/)| [C++](./algorithms/cpp/palindromePartitioning/palindromePartitioning.cpp)|Medium|
 |130|[Surrounded Regions](https://leetcode.com/problems/surrounded-regions/)| [C++](./algorithms/cpp/surroundedRegions/surroundedRegions.cpp)|Medium|
 |129|[Sum Root to Leaf Numbers](https://leetcode.com/problems/sum-root-to-leaf-numbers/)| [C++](./algorithms/cpp/sumRootToLeafNumber/sumRootToLeafNumber.cpp), [Python](./algorithms/python/SumRootToLeafNumbers/sumNumbers.py)|Medium|
-|128|[Longest Consecutive Sequence](https://leetcode.com/problems/longest-consecutive-sequence/)| [C++](./algorithms/cpp/longestConsecutiveSequence/longestConsecutiveSequence.cpp)|Hard|
+|128|[Longest Consecutive Sequence](https://leetcode.com/problems/longest-consecutive-sequence/)| [C++](./algorithms/cpp/longestConsecutiveSequence/longestConsecutiveSequence.cpp), [Python](./algorithms/python/LongestConsecutiveSequence/LongestConsecutive.py)|Medium|
 |127|[Word Ladder](https://leetcode.com/problems/word-ladder/)| [C++](./algorithms/cpp/wordLadder/wordLadder.cpp)|Medium|
 |126|[Word Ladder II](https://leetcode.com/problems/word-ladder-ii/)| [C++](./algorithms/cpp/wordLadder/wordLadder.II.cpp)|Hard|
 |125|[Valid Palindrome](https://leetcode.com/problems/valid-palindrome/)| [C++](./algorithms/cpp/validPalindrome/validPalindrome.cpp), [Java](./algorithms/java/src/validPalindrome/ValidPalindrome.java)|Easy|

Diff for: algorithms/python/LongestConsecutiveSequence/LongestConsecutive.py

@@ -0,0 +1,18 @@
+def longestConsecutive(self, nums):
+    
+    #first, create a hashmap
+    hm = set(nums)
+    longest = 0
+    #find the longest consecutive sequence from each number in the new
+    #hashmap (set)
+    for num in hm:
+        if (num - 1) not in hm:
+            current = num + 1
+            cons = 1
+            while current in hm:
+                current += 1
+                cons += 1
+            if cons > longest:
+                longest = cons
+            
+    return longest

Diff for: algorithms/python/SingleNumberII/SingleNumberII.py

@@ -0,0 +1,15 @@
+def singleNumber(self, nums):
+           
+    #1. make hashmap
+    #2. while traversing list, add each element
+    #3. remove it once it has been seen 3 times
+    #4. finally, the only value left is the one we're looking for
+    
+    hashmap = defaultdict(int)
+    for num in nums:
+        hashmap[num] += 1
+        if hashmap[num] == 3:
+            del hashmap[num]
+            
+    singleNum = hashmap.keys()[0]
+    return singleNum